Electric etching instrument



E. F. HANKIN. ELECTRIC ETcHmG INSTRUMENT.

APPLICATION FILED AUG.23. |920.

Patend Aug. 9, 1921.

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PATENT OFFICE.

F. HANKIN, OF PHILADELPHIA,PENNSYLVANIA.

ELECTRIC ETCHING INSTRUMENT.

Specification of Letters Patent.

Patented Ang'. 9, 1921.

. Application led August 23, 1920. Serial No. 405,346.

To all lwhom t may concern: v

Be it known that I, EDWARD F. HANKTN, a citizen of the yUnited States, residing at Philadelphia, in thecounty of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Electric Etching Instruments, of which the following is a specification. y

One object of my invention is to provide an improved instrument which can be used in the manner of a pencil to write upon or otherwise mark metal so that the writing or marking will be actually etched by heat caused by a rapid succession of electric arcs. Another object is to so construct my improved instrument that it can be freely and quickly moved by the hand and will therefore be an improvement over instruments previously made for said purpose and which often stick due to irregularities in the contact and depth of marking. y A still further object is to provide an instrument which will produce the etching in i Such manner that it 'will be leven and more distinct than heretofore possible and so deep that it cannot be readily obliterated. y

- These objects,k and other advantageous ends which will befdescribed hereinafter, I attain in the following manner, reference being had to theaccompanying drawings in whichi n y Figure 1 fis a top plan View of an electric etching instrument made in accordance with vmy present invention, and i Fig. 2 is a longitudinal section taken een`w trallyon Fig. land showing certain of the innermost parts in outside view.

Referring tothe drawingsj represents a brass tube which isfscrewed at one end into a head 4. This head 4 may bemade of brass and includes two annularly projecting flan ges 5 and 6 so as to provide a spool portion 'upon which is wound a number rof wrappings ot insulated electric conduit wire 7 The head 4 has a chamber 8 immediately vto the rear of the tube 3 and in this chambery slides a core 9 preferably of soft iron; said core being connected to a rod 10 which is prefer-v i ably made of brass. The rod 10 is slidably mounted within the tube 3 and at its outer end, which projects beyond the outer end of the tube 3, is provided with a copper etching member 11 hereinafter termed i a point, This etching point may be screwed or otherwisek secured upon the rod 10 so that it may be removed and the etching point has a conical-portion 12 for a purpose hereinafter described. A cap 13 has a portion 14 which is screwed within the end of the chamber 8 opposed to the core 9 and a coiled spring 15 is vinterposed between the core 9 and the portion 14 oit' the cap 13 and serves to normally move the core 9 and rod 10 forwardly or in 'other words into the position shown in Fig.

2 with a part of the core 9 located forwardly o'l the wire coil 7. The wire of the coil. 7 may be either enameled or insulated in any other suitable manner and one end ot this coil is grounded upon the head 4. The other end 16 ot the wire of the coil is secured to a binding post 17 as shown and a feed wire 18 is alsoconnected to the binding post by means of a thumb screw 19. This feed wire may lead from one pole of an electric generator or other source of current and'the other pole of said generator will be grounded upon the metal whichis to be etched.

The tube 3 is covered by an outer insulating sleeve 20. The binding post 17 extends through a. band 21 of insulating material which surrounds the forward portion of the head 4. A.k clamp 22 is secured on the forward end of the sleeve and is 4'split at one side so res tosupport an adjustable guide shoe 23 gsaid 'guide shoe having annpwardly curved portion 24 directlyunder the conical end 12 of the etching point 11 and I preferably make the extreme endrof the curved portion24 of the shoe globular' or enlarged as illustrated. v

In the use oi my invention the instrument is held in the same 'manner as apencil yand consideringthat a plate of metal is lto be etched either by writing or other marking Vthe curved portion. 24 of the guide shoe 23 afterward the instrument is swung` on the portion 24 as a fulcrum or bearing until the extreme end of the conical portion 14- oi the etching point engages the ,surface yof the plate to be' etched. This will complete an electric circuit through theV coil 7 and will 'cause the core 9to be Vdrawn into the ieldor Zone of the windings ofthe coil 7 in the same manner as a solenoid. This movement of the core will cause the rod 10 to be moved and the etching point to be raised from the plate. In so doing an electric arc or V*dame will be produced which will locally melt the upper portion of the plate. However, as soon as the point 11 has been lifted from the plate due to the action of the solenoid coil 7, the

is no possibility7 of the instrument sticking 'due to the contact or deptn of marking. A

distinct marking can be made of such depth that it cannot readily be obliterated and any kind of metal which will conduct electricity can be readily etched by my improved instrument.

By having the enlarged or globular end on the guide shoe Q3, a smooth contact can be made with the article which is to be etched up to the time in which the etching point engages said article and in this manner the instrument can be freely and easily used for writing purposes without undue friction between the shoe and the article which is to be etched.

While I have described my invention as taking a particular form, it will be understood that t-he various parts of my invention may be changed without departing from the spirit thereof, and hence I do not limit myself to the precise construction set forth, but consider that I am at liberty to make such changes and alterations as fairly come within the scope of the appended claims.

I-Iaving thus described my invention, what I claim as new and desire to secure by Letters Patent is l. An etching instrument of the character described including an etching point and a solenoid operative to move said point out of electric` contact with material to be etched; substantially as described.

i2. An etching instrument of the character described including a head having a chamber; aA core slidable within said chamber; an electric conduit wire coil on said head surrounding said chamber; a spring for moving said core in a direction away from the field of said coil; and an etching point connected to said core and movable into engagement with an article to be etched whereby an electric circuit is completed through the point and said coil, and said coil is operative to move the core and thereby withdraw the etching point from said article to break the circuit; substantially as described.

An etching instrument of the character described including a head having a chamber; a core sli'dable within said chamber; a tube connected to said head; a rod slidably fitting said tube and connected to said core and etching point on said rod and located outside of said tube;` an electric conduit coil surrounding said head and said chamber; a spring for moving said core in a direction out of the field of said coil, said coil having one end grounded upon said head; and means for connection of the other end of said coil with one pole of an electric generator, said core. rod and etching point forming an electric conduit in connection with said head whereby when the other pole of said generator is grounded on the article to be etched and the etching point is brought in contact with said article, the coilwill be energized to draw said core into its field and the etching point will be moved away from the article to cause an are and the consequent etching of the article, said spring being operative to again move the etching point into engagement with said article; substantially as described.

An etching instrument including a'supporting structure; an etching pointsupported by said structure; and a guide shoe insulated yfrom said etching point and adjustable into various positions relatively to said etching point; substantially as described. y

5. iin etching instriunent including a supporting structureyan etching point suppor d by said structure; and a guide shoe insulated from said etching point7 said Iguide shoe having a portion curved toward said etching point; suliistantially as described.

G. ein etching instrument including a supporting structure; an etching point supported by said structure; and a. guide shoe insulated from said etching point7 said guide shoe having an enlarged curved portion located adjacent said etching point; substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

`EDWARD F. HANKIN.

IVitnesses ELIZABETH GARDE, CHas. E. Po'r'rs.

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